export {};
let num: number = 10;

let arr: (number | boolean)[] = [1, 2, true];

type AddFn = (a: number, b: number) => number;
let add: AddFn = (a, b) => {
  return a + b;
};

/* 
ts的开发技巧
1. 正常写完JS的代码
2. 把鼠标摸到变量上面，利用代码提示，找到类型描述
*/
